Luteal Phase question

I have a question - I'm unsure if there is a easy answer for this however.  I was supposed to have ovulated around July 11th or 12th.  We BD'd that week but I woke up just a minute ago to use the bathroom and discovered my period had come -----and I'm not due until the 25th of the month.  Needless to say I'm rather upset.  I'm confused by the luteal phase though because I was playing around with the numbers and discovered that it changes when your fertile.  So I'm wondering how am I supposed to figure out the length of mine.  I don't think mine is 14 days long........the last time I got pregnant I was charting my periods and noticed I ovulated last October 12th - and I we did have sex that day and I got pregnant.  That was according to the 14 day phase, but since the m/c, can my phase have become longer?  I'm so confused and want to try again next month, but don't wanna miss the chance because I'm not calculating my phase right, if I got 15 or 16 (the highest it goes up to) my fertile period changes by a week or so, so it's a big deal.  If anyone can help me figure this out I'd be thrilled.  Normally my cycle days are either 34-36 days long.  Please help!
Thanks.

[tarajanes]

Hi your luteal phase is effected by ovulation,some women ovulate later due to stress etc..or even earliar.hence the different luteal phase.i occasionally had 16 day luteal phases..mine before i concieved this cycle has been 12 days long.so luteal phases are always the same give or take 1 to 2 days,since sperm can survive up to 5 days this isnt a big deal and unlikely to stop conception,do you chart,or use ovulation tests,if your cycles vary it would be helpful.mc do effect your cycles so i would suggest doing the above.i wish you the best of luck..

[tarajanes]

You most likely ovulate around cd20 to cd22..